The present invention relates to a cooling unit for facilitating the radiation of heat from heat-generating components such as semiconductor packages, and also an electronic apparatus incorporating the cooling unit.
In recent years, portable electronic apparatuses, typified by book-like portable computers and portable information tools, have been provided. Each of these apparatuses incorporates an MPU (Micro Processing Unit) designed to process multimedia information, such as characters, speech, sound, and images. The data-processing speed and the number of functions of the MPU have continuously increased. The higher the speed the MPU processes data and the more functions it performs, the more electric power it consumes. The amount of heat the MPU generates while operating increases in proportion to the power it consumes. In the case of a portable computer incorporating an MPU, the heat generated by the MPU must be radiated efficiently from the MPU in the housing of the portable computer. It is therefore absolutely necessary to provide a cooling unit in the computer housing to cool the MPU.
Jpn. Pat. Appln. KOKAI Publication No. 10-51170 discloses a conventional cooling unit. The cooling unit comprises a heat sink, a heat-conducting duct, a heat pipe and a fan. The heat sink has a heat-receiving portion and a heat-radiating portion. The heat-receiving portion is thermally connected to an MPU. The heat-radiating portion receives heat from the heat-receiving portion. The heat-radiating portion is remote from the heat-receiving portion. The heat-conducting duct is secured to the heat-radiating portion of the heat sink. The heat-conducting duct has an inlet port and an exhaust port. Air is supplied into the duct through the inlet port and exhausted from the duct through the exhaust port. Both the inlet port and the exhaust port open to the outside the housing of a computer.
The heat pipe is arranged, extending along the heat sink. The heat pipe thermally connects the heat-receiving portion and the heat-radiating portion. Hence, the heat generated by the MPU is effectively transferred from the heat-receiving portion to the heat-radiating portion through the heat pipe.
The fan is provided in the heat-conducting duct. When the fan is driven, air is drawn into the duct through the inlet port of the duct. In the duct the air flows to the exhaust port, cooling the heat-radiating portion of the heat sink. The heat of the MPU, transmitted to the heat-radiating portion, is thereby radiated from the housing in the form of heated air.
In the conventional cooling unit, the heat transmitted from the MPU to the heat-receiving portion is transferred to the heat-radiating portion by virtue of heat conduction to the heat-radiating portion and by way of the heat pipe and is radiated from the heat-radiating portion.
The housings of portable computers developed recently are made thin and compact. The heat sink of the cooling unit provided in the housing needs to be small, too. Therefore, the heat sink cannot have a sufficient thermal capacity. The resistance to the heat propagating in the heat sink inevitably increases. Consequently, it cannot be expected that the heat conducted through the heat sink be radiated with high efficiency.
In the conventional cooling unit, the transfer of heat from the heat-receiving portion to the heat-radiating portion cannot help but largely depend on the heat pipe. It is difficult to transmit the heat of the MPU to the heat-radiating portion with high efficiency. The cooling unit should therefore be improved further in terms of the efficiency of radiating heat from the MPU.
The portable computers hitherto developed have heat-generating circuit components each, such as a power-supply circuit unit and a memory. These circuit components are provided in the housing of the computer, together with the MPU. There is the trends that the amount of heat that the circuit components generate while operating gradually increases. The amount of the heat these components radiate is therefore too large to neglect, and is one of the causes of raising the temperature in the housing.
The conventional cooling units are all designed to cool the MPU only. The circuit components other than the MPU are located outside the route of the heat-conducting path, provided in the cooling unit. The temperature in the housing inevitably rises, due to the heat generated by these circuit components. This increases the ambient temperature of the MPU, adversely influencing the operation of the MPU.
The first object of the present invention is to provide a compact cooling unit that can efficiently cool a heat-generating component.
The second object of the invention is to provide a compact cooling unit that can efficiently cool a plurality of heat-generating components, without requiring a large installation space.
The third object of the invention is to provide an electronic apparatus in which a heat-generating component can be cooled efficiently and the housing of which can be made small with ease.
To attain the first and second objects, a cooling unit according to the first aspect of the invention comprises a heat-receiving portion and a heat-exchanging portion. The heat-receiving portion receives the heat generated by a heat-generating component. The heat-exchanging portion receives heat from the heat-receiving portion. A part of the heat the heat-generating component generates is transferred to the heat-exchanging portion through heat-transferring means. An air-supply means is located between the heat-receiving portion and the heat-exchanging portion, for supplying cooling air from the heat-receiving portion to the heat-exchanging portion.
To achieve the third object of the invention, an electronic apparatus according to the second aspect of the invention comprises a heat-receiving portion, a housing, and a heat-exchanging portion provided in the housing. The heat-receiving portion receives the heat generated by a heat-generating component. The heat-exchanging portion receives heat from the heat-receiving portion. A part of the heat the heat-generating component generates is transferred to the heat-exchanging portion through heat-transferring means. An air-supply means is located between the heat-receiving portion and the heat-exchanging portion, for supplying cooling air in the housing from the heat-receiving portion to the heat-exchanging portion.
In both the cooling unit and the electronic apparatus, the heat generated by the heat-generating component is diffused as it is conducted from the heat-receiving portion to the heat-exchanging portion. A part of the heat transmitted from the heat-generating component to the heat-receiving portion is transferred to the heat-exchanging portion via the heat-transferring means.
Since the heat-exchanging portion receives the cooling air supplied by air-supply means, the heat of the heat-generating component is radiated into the atmosphere as the cooling air flows into the atmosphere. When the air-supply means supplies cooling air from heat-receiving portion to the heat-exchanging portion, the cooling air flows along the heat-receiving portion. The heat-receiving portion is therefore cooled by virtue of not only the transfer of heat accomplished by the heat-transferring means, but also the forced convection of the cooling air.
Both the air-cooling of the heat-receiving portion and the heat transfer from the heat-receiving portion to the heat-exchanging portion are utilized in order to radiate the heat from the heat-receiving portion with high efficiency. This makes it possible to reduce the thermal capacity in the heat-conducting path that extends from the heat-receiving portion to the heat-exchanging portion. The heat-receiving portion and the heat-exchanging portion can be made compact. Moreover, the housing need not have a large space to accommodate the cooling unit. It is therefore easy to render the housing thin and small.
To attain the first and second objects, a cooling unit according to the third aspect of the invention comprises a heat-receiving portion and a heat-exchanging portion. The heat-receiving portion receives the heat generated by a heat-generating component. The heat-exchanging portion receives heat from the heat-receiving portion. A part of the heat the heat-generating component generates is transferred to the heat-exchanging portion through heat-transferring means. An air-supply means is located between the heat-receiving portion and the heat-exchanging portion. The air-supply means has a first air-supplying port and a second air-supplying port. The first air-supplying port is provided to supply cooling air to the heat-exchanging portion. The second air supplying-port is provided to supply cooling air to the heat-receiving portion.
In the cooling unit thus constructed, the heat generated by the heat-generating component is diffused as it is conducted from the heat-receiving portion to the heat-exchanging portion. A part of the heat transmitted from the heat-generating component to the heat-receiving portion is transferred to the heat-exchanging portion via the heat-transferring means.
Since the heat-exchanging portion receives the cooling air supplied through the first air-supplying port, it is cooled by virtue of forced convection of the cooling air. Hence, the heat of the heat-generating component transferred to the heat-exchanging portion is radiated into the atmosphere as the cooling air flows into the atmosphere. Since the air-supply means supplies cooling air to the heat-receiving portion through the second air-supplying port, the heat-receiving portion is cooled by virtue of the forced convection of the cooling air, too. As a result, the efficiency of radiating heat from the heat-receiving portion can increase, due to not only the heat transfer achieved by the heat-transferring means but also the forced convection of cooling air.
Both the air-cooling of the heat-receiving portion and the heat transfer from the heat-receiving portion to the heat-exchanging portion are utilized in order to radiate the heat from the heat-receiving portion with high efficiency. This makes it possible to reduce the thermal capacity in the heat-conducting path that extends from the heat-receiving portion to the heat-exchanging portion. The cooling unit can therefore be made compact, thus requiring no large installation space.
To attain the first and second objects, a cooling unit according to the fourth aspect of the invention has two heat-receiving portions and one heat-exchanging portion. The heat-exchanging portion receives the heat generated by a first heat-generating component and transmitted to the first heat-receiving portion. It also receives the heat generated by a second heat-generating component and transmitted to the second heat-receiving portion. The first heat-receiving portion is thermally connected to the heat-exchanging portion by first heat-transferring means. Similarly, the second heat-receiving portion is thermally connected to the heat-exchanging portion by second heat-transferring means. The heat-exchanging portion receives cooling air supplied by air-supply means.
To achieve the third object of the invention, an electronic apparatus according to the fifth aspect of the invention comprises a housing and a heat-exchanging portion provided in the housing. The heat-exchanging portion receives the heat generated by a first heat-generating component and transmitted to a first heat-receiving portion. The heat-exchanging portion receives also the heat generated by a second heat-generating component and transmitted to a second heat-receiving portion. The first heat-receiving portion is thermally connected to the heat-exchanging portion by first heat-transferring means. Similarly, the second heat-receiving portion is thermally connected to the heat-exchanging portion by second heat-transferring means. The heat-exchanging portion receives cooling air supplied by air-supply means.
In both the cooling unit and the electronic apparatus, the heat transmitted from the first heat-generating component to the first heat-receiving portion is transferred to the heat-exchanging portion via the first heat-transferring means. Similarly, the heat transmitted from the second heat-generating component to the second heat-receiving portion is transferred to the heat-exchanging portion via the second heat-transferring means.
Since the heat-exchanging portion receives the cooling air supplied through the air-supply means, it is cooled by virtue of forced convection of the cooling air. The heat of the first and second heat-generating components, transferred to the heat-exchanging portion, is therefore radiated from the housing as the cooling air flows from the housing. Thus, the two heat-generating components can be cooled uniformly by means of one heat-exchanging portion. This can maintain the ambient temperatures of both heat-generating components at appropriate values.
In the electronic apparatus, the heat generated by the first heat-generating component and the heat generated by the second heat-generating component are collected at one position. Hence, two air-supply means need not be provided for the two heat-generating components, respectively. Nor is it necessary to use a large heat-receiving portion that extends over both heat-generating components. The cooling unit for use in the electronic apparatus can therefore be made compact. It follows that the housing of the electronic apparatus need not have a large space to accommodate the cooling unit. This renders it easy to make the housing thin and small.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.